Optical hyperpolarization and NMR detection of 129Xe on a microfluidic chip

Optically hyperpolarized 129Xe gas has become a powerful contrast agent in nuclear magnetic resonance (NMR) spectroscopy and imaging, with applications ranging from studies of the human lung to the targeted detection of biomolecules. Equally attractive is its potential use to enhance the sensitivity of microfluidic NMR experiments, in which small sample volumes yield poor sensitivity. Unfortunately, most 129Xe polarization systems are large and non-portable. Here we present a microfabricated chip that optically polarizes 129Xe gas. We have achieved 129Xe polarizations >0.5% at flow rates of several microlitres per second, compatible with typical microfluidic applications. We employ in situ optical magnetometry to sensitively detect and characterize the 129Xe polarization at magnetic fields of 1 μT. We construct the device using standard microfabrication techniques, which will facilitate its integration with existing microfluidic platforms. This device may enable the implementation of highly sensitive 129Xe NMR in compact, low-cost, portable devices.